Mustard Mountain is located in the northern quadrant of the Mirror World. Although it seems like a peaceful mountain at first, Kirby eventually discovers that it is actually an active volcano as he ventures deeper into it. While the base is a calm mountainside, the peak of the mountain is filled with constantly flowing lava. Like all volcanic levels in the series, it is of vital importance that Kirby evades the lava. Kracko inhabits the mountain's tallest peak, ready to challenge Kirby for the third Mirror Shard.